Microelectromechanical systems (MEMS) include micromechanical elements, actuators, and electronics. Micromechanical elements may be created using deposition, etching, and or other micromachining processes that etch away parts of substrates and/or deposited material layers or that add layers to form electrical and electromechanical devices. One type of MEMS device is called an interferometric modulator. As used herein, the term interferometric modulator or interferometric light modulator refers to a device that selectively absorbs and/or reflects light using the principles of optical interference. In certain embodiments, an interferometric modulator may comprise a pair of conductive plates, one or both of which may be transparent and/or reflective in whole or part and capable of relative motion upon application of an appropriate electrical signal. In a particular embodiment, one plate may comprise a stationary layer deposited on a substrate and the other plate may comprise a movable reflective layer (also referred to as a mechanical layer herein) separated from the stationary layer by a transparent medium (e.g., an air gap). As described herein in more detail, the position of one plate in relation to another can change the optical interference of light incident on the interferometric modulator. Such devices have a wide range of applications, and it would be beneficial in the art to utilize and/or modify the characteristics of these types of devices so that their features can be exploited in improving existing products and creating new products that have not yet been developed.
Interferometric modulator displays typically include light absorbing areas (or light absorbing masks)—e.g., composed of black matrix—to improve a display contrast of the interferometric modulator displays. FIG. 1 illustrates a portion of a conventional interferometric modulator display 100 including a stationary layer 102 (formed on a substrate 104) and a movable reflective layer 106. As shown in FIG. 1, the interferometric modulator display 100 also includes a black matrix layer 108 formed on the substrate 104. The interferometric modulator display 100 further includes posts 110—formed over of the black matrix layer 108—that support the movable reflective layer 106. Formation of the posts 110 over the black matrix layer 108, however, typically causes a “launching” of the movable reflective layer 106 over the substrate 104 which can increase the size of an air gap 112 between the stationary layer 102 and the movable reflective layer 106. The increase in size of the air gap 112 can cause an undesirable shift in an optical response of an interferometric modulator display. Such a shift in optical response is noticeable especially in broadband white interferometric modulator displays which require a tight control over the size of air gaps.